Autotransfusion refers to the reinfusion of a medical patient's own blood. Homologous infusion refers to a blood transfusion where the blood is collected from a donor and transfused to a compatible patient. Autotransfusion is preferred since no testing of the blood is required because the blood transfused is that of the patient and further, since the patient will not be subjected to the possibility of a blood carried disease, such as hepatitis, AIDS, etc. Additionally, autotransfused blood is more fresh than "banked blood" and contains the patient's own antibodies.
Autotransfusion is categorized into three categories. First, "pre-operative" where the patient donates his or her own blood prior to scheduled surgery and the blood is stored for that patient's later use. Second, "intra-operative" when during the course of surgery, the shed blood is collected, filtered, washed, and reinfused back into the patient. Thirdly, "post-operative" where following surgery, blood drainage is collected and reinfused into the patient. Post-operative autotransfusion is limited in use since there are strict criteria for the type of blood which can be reinfused. Currently, the only post-operative blood believed suitable for autotransfusion is mediastinal blood, i.e. the blood which comes from the anatomical space or cavity in the chest where the heart is located.
Underwater chest drainage units are presently used in the post-operative care of patients having surgery involving entry into the chest. Chest drainage units are also used in trauma cases and certain medical applications which require the removal of fluids and air from inside the chest cavity. The chest drainage unit removes fluid or air from a chest cavity by the use of catheters placed in the chest cavity at the end of surgery. The chest drainage unit is connected to a vacuum source which applies a suction to the chest tubes to remove the drainage and trapped air from within the patient.
The use of an autotransfusion unit in combination with a chest drainage unit is known in the art. For example, U.S. Pat. No. 4,445,884 discloses an autotransfusion unit for collecting blood and purZging air from the collected blood attached to an underwater drainage system, such as a chest drainage system. The unit disclosed in the '884 patent, however, while connected to a drainage system, collects blood directly from the patient through an inlet tube attached to the tubing aspirating blood from the patient to the drainage system. The autotransfusion unit disclosed in the '884 patent is connected to the drainage system for the purpose of maintaining the negative pressure on the collection chamber of the unit due to a suction source attached to the drainage system and for the purpose of drawing out the air purged from the blood in the collection chamber. Once the blood is purged of air, the blood is taken from the collection chamber and reinfused into the patient. Clamps are used to control the flow of blood, purged air, and vacuum pressure of the chamber. The structure of the collection chamber discussed in the '884 patent is more fully disclosed in U.S. Pat. No. 4,424,053 which is referred to in the '884 patent by Ser. No. 290,666, filed Aug. 5, 1981. U.S. Pat. No. 4,540,413 discloses a cardiopulmonary drainage collector having a blood transfer adaptor. The '413 patent is directed to the structure of a drainage collector which has a chamber for collecting blood from a patient. The patent discloses that the blood collected in the chamber can be removed from the chamber by a blood transfer needle connecting tube which punctures a seal in the chamber. The connecting tube is attached to a standard blood bag used for collecting transferred blood. Once the blood bag is filled, it can be processed for reinfusion.
Two specific systems currently on the market which incorporate autotransfusion with chest drainage are the Sorenson "RECEPTAL" and Deknatel's "Pleur-Evac ATS". The Sorenson product utilizes a plastic bag which is placed inside the collection chamber of a chest drainage unit. The bag is in a negative pressure container and collects the blood drainage coming into the collection chamber. When the bag is filled, the bag is removed from the negative pressure container and connected to a reinfusion system. During the removal of the blood collection bag and container, however, the connecting tubes are clamped off and the patient is temporarily disconnected from the chest drainage unit and the negative pressure which is required to hold the chest cavity at proper breathing levels. The changeover requires numerous steps which are difficult and time consuming to accomplish. The Deknatel product utilizes an autotransfusion collecting bag in the tubing which is part of the chest tubes connecting the patient's chest to the chest drainage unit. This technique involves an "open" system, i.e. during the disconnection of the blood collecting bag, the blood is exposed to the ambient atmosphere. As with the Sorenson product, the tubes joining the patient's chest cavity to the chest drainage unit must be clamped off during the changeover process.
Further, blood collection units of various structures are known in the art. For example, U.S. Pat. No. 4,573,992 discloses an apparatus for aspirating and reinfusing blood under pressure which in one embodiment comprises a rigid container enclosing a deformable inner container having a space between the outer container's inner walls and the inner container's outer walls. The deformable and rigid containers are connected to a suction line which aspirates blood into the inner container through an aspirator tube which is connected to another portal in the apparatus. The inner deformable container does not collapse during collection of blood due to the pressure in the space existing between the outer rigid container and the inner container. The pressure is applied from a pressure source which is attached to the rigid container at a side portal which pressurizes the space between the outer and inner containers. A plug can be inserted into the pressure connection portal to maintain the pressure in the space between the containers. When the collection of blood is completed, the inlet which is connected to the suction source is disconnected and the collection unit is then connected to an infusion set so that the collected blood can be reinfused into the patient. Additionally during reinfusion of the blood, the inlet connected to the pressure source is opened so that a controlled feed of pressure medium enters the space between the outer rigid container and the deformable inner container thereby applying pressure to the outside of the inner container causing the blood in the inner container to be fed through the infusion set. The patent does not disclose connecting the apparatus to a drainage system. U.S. Pat. No. 4,402,687 discloses a suction collection system for collecting blood from a patient for reinfusion into the patient. The collection system comprises a rigid hollow canister having a thin flexible plastic sheet material covering the entire outer surface of the canister to form an airtight receptacle. The apparatus contains a first portal in the top wall of the canister which is connected to a vacuum source for reducing the pressure within the receptacle. A second portal in the canister is connected to an aspirator for collecting blood and other body fluids from a patient. Fluid within the receptacle is removed through a normally closed outlet port in the bottom of the canister. An air inlet port is also contained in the top surface of the canister. It is further disclosed that rather than using an aspirator, a chest tube or other similar drainage device can be utilized. U.S. Pat. No. 4,564,359 discloses an autotransfusion unit for collecting blood to be used for retransfusion. The autotransfusion unit contains a bottom inlet attached to a vacuum source for drawing blood into the collection chamber, an upper inlet through which the blood enters the collection chamber, and an upper outlet through which the blood exits the collection chamber when the autotransfusion unit has been disconnected from the patient and inverted. The collection chamber of the autotransfusion unit is divided into two portions a bottom gas filled space which is separated from an upper portion which receives the collected blood.
The art does not disclose a blood collection and reinfusion unit having the combined structure of the present invention used in conjunction with a chest drainage unit for the autotransfusion of blood in accordance with the method of the present invention.